Pumping apparatus



Sept. 26, 1933. F, w, Hmm@ www? PUMPING APPARATUS Filed Sept. 25, 1927 5 Sheet's-Shee l 3j LWENTOR. MT @f4/ Sept. 26, 1933. F w H|| D 1,927,831

A PUMPING APPARATUS Filed Sept. 23, 1927 5 Sheets-Sheet 2 Tw/ Pump 54 53 Reb/ers@ Gear @Seil/afar a 1N VENTOR,

TTORNEY Sept. 26, 1933. F W HILO 1,927,831

PUMP ING APPARATUS Filed Sept. 23, 1927 5 Sheets-Sheet 3 Swivel Cla/HP l D UV VENTOR,

Sept. 26, 1933. F. w. HILD 1,927,831

PUMPING APPARATUS Filed Sept. 25, 1927 5 Sheets-Sheet 4 INVENTOR.

A TTORNE Y Gsell/afar ,25

Sept. 26, 1933. F. w. HIL@ PUMPING APPARATUS Filed Sept. 23. 1927 5 Sheets-Sheet 5 NVENTOR.

/ AT/ORAEY Patented Sept. 26, 1933 UNITED STATES PATENT OFFICE PUMPINGl APPARATUS Application September 23, 1927 Serial No. 221,418

8 Claims.

My invention relates to pumping apparatus and ithas particular application to oil well pumping systems.

The use of a long stroke in the pumping of oil wells has many important advantages over the short stroke, which accrue substantially in proportion to the lengthl of the: pumping stroke.

An object of my invention is to provide means for effecting a complete up and down stroke of i0 the pump. for each reversal of the motor operated cable winding drum.

, Another object of my invention is to utilize the kinetic energy of the descending pumping string thereby lessen the stress in said mechanism and to eliminate the disturbance and surges of the power supply and to lessen the stress in the driving mechanism when reversing said mechanism.

Still-another object of my invention is to provide an improved reversal regulator `and oscillator control device for effecting either reciprocating motion or oscillatory rotation of a. work device.

Other objects of my invention will become evident from the following description taken in con- 5' junction with the accompanying drawings.

The invention consists of the novel parts and combination of parts to be described hereinafter, all of whichcontributeto produce an eiiicient pumping apparatus.

30- A preferred embodiment of the invention is described in the following specification, while the broad scope of the invention is pointed out in the appended claims.

In the drawingsy I Figure 1 is a view in elevation of a pumping equipment organized in accordance with and utilizing the principles of my invention;

Fig. 2 is a plan view of the pumping drive and con-trol apparatus shown in Fig. 1;

40 Fig. 3 is a plan view of a drive equipment organized in accordance with my invention and utilizing an engine which may be either of the steam or internal combustion type;

Fig. 4 is a view of a part of my improved hoist drum, showing in end elevation the swivel clamp for securing a cable to the winding drum;

Fig. 5 is'a view in vertical section of part of the drum and the swivel clampv shown in Fig. 4;

, taken along the line V-V of Fig. 4;

Fig. 6 is a View in horizontal section of the device showny inFig. 4 and Fig. 5, taken along Ythe line VI--VI of Fig. 5;

Fig. 7 is a view in end elevation of my improved reversal regulator and oscillator device;

` Fig. 8 is a view in horizontal section of the (Cl. S-212) oscillator shown in Fig. 7', taken along the line VIII-VIII thereof Fig. 9 is a View in side elevation of the oscillator shown in Fig. 7 and Fig. 8';

Fig; 10 is a fragmentary view of a spur gear 69- and. pinion shown in Fig. 8;

Fig. 11 isa view in horizontal section of my improved speed changing power transmission, taken along the line XI-XI of Fig. 12, and

Fig. 12' is a view in side elevation of the trans- 65 mission device shown in Fig.. 1I.

Referring to the drawings, the apparatus embodying my invention may be applied to an oil well comprising the usual casing 1 within which may be suspendeda tubing 5. having at its lower 7 end a perforated liner or end closure 2- for admitting oil' or other liquid. The lower portion ofV the tubing 5 constitutes a relatively long working barrel or cylinder 4 within which a piston 61 is disposed, to be reciprocated by means of a string 5 of sucker rods 8 that extend through a stuffing box 10 at the top of the tubing 5.

To prevent the oil being pumped, from rcturning to the liner 2 during the down stroke of the piston 6, a standing value 3 is provided at 8' the junction of the liner 2r with the tubing 5'. The oil may be conducted from the well by means of a pipe 13 that is connected to the top of the tubing 5 below the stuiiing box 10.

The upper end ofthe sucker rod 8 is secured 8.5 to one end of a cable or wire line 9 that passes over an idler sheave 11 which may be supported in any convenient manner near the top of a standard derrick (not shown).

Thev other end of the wire line 9 is fastened to a winding drum 14 in such manner that it may be wound in either direction thereon to raise the piston 61. The drum 14 is mounted on a shaft l5 that may be called the output shaft, and which is rotatablyv supported insuitable bearings 16 upon the working platform of the oil well. To actuate the drum 14 a motor driven reduction gear device 20 is provided together with an oscillator mechanism anda suitable motor controller for regulating the direction of rotation thereof, as set forth in detail hereinafter.

In order that the drum 14 may be held against rotation, brake bands 17 are provided. The brake bands 17 may be held open while the drum is actuated preferably by means of my electromagnetic brake control that is described in my Patent No. 1,558,876, granted October 27, 1925. This brake control mechanism operates to automatically apply the brake in case the supply of electrical energy isl interrupted.

When in operation, the drum 14 is rotated to unwind the wire line 9 to its full extent to lower the piston 6 and then, continuing in the same direction the drum winds up the wire line 9 to raise the piston 6. When the piston reaches the top of its stroke, the oscillator 25 functions to reverse the direction of rotation of the drum 14 and the lowering and raising process is repeated. In this manner one complete downward and upward stroke cycle is accomplished for each reversal of the direction of rotation of the drum 14.

Reference may now be had to Fig. 4, Fig. 5 and Fig. 6, which illustrate a swive clamp 12 for securing the wire line 9 to the drum 14.

The swivel clamp 12 comprises a disc 69a with a lug 70 extending diametrically across its outer face and with a spool 72 extending perpendicularly from its inner face; the spool terminates in a flange 73. The lug 70 has a hole 71 ex-lA tending through it, so that the wire line 9 may pass from the outerface through to the inner face, in order that the wire line may be wrapped around itself on spool 72 and secured thereto by a snub hitch or any other convenient means. The lug 70 is symmetrically shaped and when in position on the drum 14, the exposed portion has the contour and proportions of the wire line 9 when wound on the drum.

An opening 69 is made in the drum 14 at a place where the drum flange meets the cylindrical cable winding surface. The opening 69 is shaped to receive the swivel clamp 12. A pin 67 is secured by a cotter pin 68 to a projection 74 that is within the drum 14 and is a part thereof. The axis of this pin 67 and of the opening 69 coincide with an element in the cylindrical cable winding surface of drum 14. The swivel clamp 12 is rotatably mounted on the pin 67 so that wire line 9 may be wound in either direction on the drum 14.

Referring to Figures 1 and 2, a sprocket 13, secured to the shaft 15, is connected by a chain 19 to a sprocket 21, of the reduction gear transmissionY device 20. Another sprocket 22 is rotatably mounted on the shaft 15. A jaw clutch 22a, splined to the shaft 15, engages corresponding jaws of the sprocket 22, which is connected by a chain 23 to a sprocket 24 of the oscillator 25. Another sprocket 26 of the oscillator 25 is connected by a chain 27 to a sprocket 28, which is rotatably mounted on the shaft of the motor controller`v30. A jaw clutch 29, splined to the controller shaft, engages corresponding jaws of the sprocket 28. A hand wheel 31 on. the controller shaft, permits independent hand operation of the motor controller when the jaw clutch 29 is shifted out of engagement with the sprocket 28.

Figure 11 and 12 show the improved transmission mechanism 20, the function of which is speed changing. It will be seen that this device is of the three-speed differential gear type, in which a pair of bevel sun gear-wheels 101 and 102 are rotatably mounted on shaft 100. Spur gear-wheels 103 and 104 are securely keyed to the sun gear-Wheels 101 and 102, respectively. The sun gear-wheels are provided with extended sleeves which serve as quill bearings surrounding shaft 100 and are supported rotatably in frame 105. The sleeve of sun gear 101 is extended beyond the frame 105, and splined upon the sleeve extension is a double jaw clutch 106 having jaws on both ends. The shaft 190 is rotatably supported by the quill bearings formed by the sun gear-wheel sleeves and has securely keyed to it, a planetary spider 107, which embodies the short shafts 108 at right angles to shaft 100. Planetary bevel gear-wheels 109 are rotatably mounted on shafts 108 and disposed to mesh with the sun gear-wheels 101 and 102. Thrust plates 110 secured to the planetary spider 107 act as thrust bearings to receive the axial thrust of the bevel sun gear-wheels.

To the end of shaft 100 is rigidly secured a jaw clutch member 111 in position to receive and engage one end of the double jaw clutch 106. The frame 105 is provided with jaws 112 adapted to receive and engage the other end of the double jaw clutch 105. Gn the opposite end of shaft 100 is securely fastened the sprocket 21.

A pinion shaft 34 is journalled in the frame 105 parallel to the shaft 100 and has rigidly secured to it, a pinion 113 which meshes with spur gearwheel 104. Rotatably mounted on the pinion shaft 34 is pinion 114, and splined to the pinion shaft is jaw clutch 115, adapted to engage pinion 114, which has jaws for that purpose. A clutch shifter 116 for moving clutch 115 inside the case formed by frame 105 may be operated by a handle 117.

Rotatably mounted on a stationary shaft 118 is an idler gear-wheel 119, which meshes with both the pinion 114 and the spur gear-Wheel 103. Shaft 118 is secured in frame 105, which forms en cil tight case in two parts for protectively enclosing all of the gear-wheels, shafts and bearings and the lubricant for them.

This speed-changing gear set 20, for any given speed of -pinion shaft 34 produces three lesser speeds at the sprocket 21, by reason of my novel application of the principle that the speed of the pianetary member of a bevel gear differential is one half of the algebraic sum of the speeds of the two sun gear-wheels, where algebraic signs of plus and minus indicate the two possible directions of sun gear rotation.-

l A `motor 32, preferably of the induction type, drives the multi-speed or reduction gear transmission device 20 through coupling 33, which unites the motor shaft with the pinion shaft 34 of the gear transmission device.

Referring now to Fig. 7 to Fig. 10, inclusive, which show the oscillator 25:

f The sprocket 24, a gear-wheel 76 and a pinion 'i7 securely keyed to a shaft 78 so that al1 will rotate together in suitable bearings in a frame 75. Rigidly secured to a second shaft is a sprocket 26, a pinion 79 that is provided with a single tooth and an overbalance weight 8l. Rotatably mounted on shaft 80 are discs 82 and 83 and a one-piece member comprising gear-wheel 85, quill sleeve 86 andv flange 87. The shaft 80 and quill 86 are supported in suitable bearings in frame 75.

The pinion 77 and the gear-wheel 85 are constantly in mesh, having teeth around their entire circumferences. The gear-wheel 76 has teeth around its entire circumference, but the pinion 79 has only one tooth. (See Fig. 10.)

Sleeve 86, which integrally joins gear-wheel and fiange 87, serves as a quill bearing within which shaft 8G is rotatably supported. Flange 2.7 has a bent lug 88 which projects outwardly from the circumference of the flange and then parallel to shaft 80, extending over the circumferences of the discs 82 and 83, for a purpose to be set forth.

VText to flange 87, on shaft 80, is disposed the disc 82, which has secured to it close to its circurnfrence and extending parallel to shaft 80,

pin 89. Next to disc 82 is disc 83 in which are placement; of; the tivo: discs during rotation.

drilled a; number of holes: on. ay circle. correspending tothe position of pin 89` and of size to receive it. Thus discs 82` and 83. are. held by pin 89k a selectively xed angular' relation, and both discs are. rotatable as. a unit on shaft 80. Discs 82 and 83` eachhasa. single tooth, designated' 92; and` 93', respectively; which project radially from the. disc. circumference, so that eachtooth lies in the.V path. of lug 88T of flange87i and, when the member comprising gearewheel 85, sleeve 86 and flange 87 is rotated, the. lug 88 will encounter tooth 92 .or tooth 9.3 and thus cause the discs 82 and V83 to `rotate on shaft. 8.0:.

Overbalance WeightA 81 isv in the form of a quadrant. Its rotational movement is limitedk to about. a. quarter of a revolution by uprightv stop posts 97. Projecting from the inner face of weight 8l isv a'tooth. 9.4 which extends over the circumferences of. discs82 and 83 and substantially parallel: to'.v shaft 8.0.. Tooth 94 is positioned radially beyond or above, lug 88` of ange 87, so that: they do not. intercept each other,V but both teeth. Sit and 98 of the discs. 82' and 83', respectively project, radially to a suiicient extent to encounter or intercept tooth 9.4 of' overbalancing weight 81. A suitably bent flat spring'95 secured to the inner face of weight 81 bears against disc 83 and forces the latter against disc 82. to prevent axial dissuita-l'nle.A space between. the inner face of the Weight 81. and the outer face of disc 83, permits the latter to be moved against the spring 95 along the shaftr 8.0.` so as to separate the discs 82' and 83 beyond the point ofl engagement by pin. 89. This construction enaloles angular adjustmentA of the disc teeth 92 andy 93 with respect to each other.

Overbalance- Weightv 81 is positioned so that the force; of gravity acts upon it to rotate shaft 89, either to the right or the left of the Vertical or neutral` point,v tor a position of rest against either of stopposts; 97.. In order to augment the force of gravity',v a ring 96, projecting outwardly beyond the outerface from the middle part of the circumferencev ofl the weight 81,. permits the. suspension of additional Weight.

A pair of holes drilled inv upright frame posts 98 receive the stopposts 97, which rest on springs 99 in the bottom of the holes.` Each stop post 97 is a cylindrical pin and'actsl as a piston on the air and spring cushion that is thus provided when the overbalance Weight 8-1 drops against. it,y thereby regulating the rate oi movement of shaft 80.y and sprocket 25.

The pinion 79: is secured to thev shaft 80 in a definite fixed angular relation` to overhalance Weigh-t Sr, so that the. singleV tooth of pinion 79 just clears and isv out of engagement with teeth of, gear-wheel 76 When the balance weight 81 is near its position of rest against either of the stop posts 97.

The operation of the oscillator 25 is as. follows: The cha-in 23,. (Fig. lf) driving from the drum sprocket 22 tov the sprocket 2e, imparts rotation to the shaft 78, gear-vvheel 76 and' pinion 77.- The overhalancev Weight 8l is in the position shown in the.' drawings, and ther shaft 89 stationary hecause gear-wheel 76L althought rotating (in the direction -o the arrow of Fig. 19,) is out or engagement with the single tooth of pinion Pinion 77 meshing with gear-,wheel 85 causes the latter with its. sleeve 86 and flange 87 to rotate at substantially elo-Wer speed than shaft 7 8.

The rotation of flange 87 in the assumed direction causes lug 88 to approach and engage tooth 93 of discA 83 yand to rotate disc 82 and disc 83 together as one, because the two discs are connected by in 89. ToothV 92, therefore, approaches and enc, es tooth 9e oi overoalance Weight ce the latter to impart rotation to shaft 8G, pniion 79, and sprocket 26. The rotation oi its single tooth to approach teeth of moved through comes and before the overhalreaclied the vertical or neugie tooth oi pinion 79. ie velocities are the are rotatively moved. y few degrees at several e until the single tooth ward, away from engageflisc S and during this movement oi shaft 80, 8l carried past the 'o c at its gravitational mer the oi.

it of shaft 80, pinion 'lie overoalance weight' e opposite stop post ent (as to speed or ves the. drum 14. For f he thus connected to 3G of the electric motor ent cf sproclf-et 26 0pance controller and reverses the ino-tor. This action results in rei le, as subsequently nkv unire, he rotation of sprocket i and the cycle of operadeecriz-ed below is re.-

direc on and so on The frequency and length oi travel of lug 88 icc lid

forward and backward A upon the angle between 'tooth and to-UV oi the discs 82 and respectively. The -gth of travel is least when teeth 92 with lug 8S h teeth 92 and s o 93 are close together lug 83 on ei'fli. pumping the lug E proportional to the travel of e oscillator parts are d of gear-Wheel 76 is or part oi the moveouite low. The raster 1 i 1 .1 ized to `move shalt 8 trol device beyond that oi the more slowly moving S7 i also to positively carry the overhalen-ce Weight 8l Protection against or or other connected r.;

ina be provids, connected by cirand operating the supply to motor 32.

84a 'to sv h la *er to ont o the power ne oi. any wehnown type. The cutout 84 is lt maximum when The length of the a o in order to speed the operation ci the con-y U This automatic cutout and the switch 37 may ifi-i secured to frame and will be actuated by a slightly prolonged movement of overbalance weight 81 beyond the normal rest position of the latter. Over-travel of the oscillator when the normal limit is reached will result in continued movementl of flange 87 and lug 88, so that overbalance Weight 81 will be forced against stop post 97, which will yield because of spring 99. This will cause overbalance weight 81 to move ngers 81a, or 81h, which project from overbalance weight 81 into engagement with the automatic emergency cutout 84 and actuate the latter to cut off the power supply and shut down the pumping plant.

The motor controller 30, which is of the ordinary starting and reversing type is mounted on a. resistance box 35. The electrical circuits of this type of motor control unit are well known in the art, and, consequently, need not be shown in detail. However, I have shown a source of energy vsupply 36, and a switch 37 for connecting the source to conductor cable 38 and motor control unit 30-35. From the latter the circuits lead through cables 39 and 40 to the stator and rotor windings, respectively, of motor 32.

The operation of the system is simple. Assume switch 37 closed, brake bands 17 free of the drum 14, as illustrated, and that clutches 22a and 29 are open, so that sprockets 22 and 28 float loosely on their respective shafts. Then by rotating the hand wheel 31 of controller 30 through a fraction of a. revolution, electric energy from supply source 36 is conducted to motor 32, which is thereby brought to speed and drives the gear train in gear transmission device 20 to impart rotation to sprocket 21 thereof, as more fully described hereinbefore.

Power is transmitted from sprocket 21 through chain 19 to sprocket 18, thereby rotating drum 14 and winding or unwinding the Wire line 9, according to the direction of rotation of drum 14. Upon rotating the hand wheel 31 back to its initial off position, the electric energy supply is cut oi and the apparatus comes to a stop. Then by further rotating the hand wheel 3l for a like fraction of a revolution, the motor 32 is brought to speed in the reverse or opposite direction, and correspondingly the direction of rotation of drum 14 is reversed.

The winding of the wire line 9 on drum 14 will impart hoisting or upward motion to the pumping string within the tubing 5, and unwinding the Wire line will impart lowering of downward motion to the pumping string. When this is done periodically for a fixed number of revolutions of the Winding drum, a denite reciprocating motion constituting the pumping stroke is imparted to the pumping string, and manifestly this stroke may be made of any length within the limits of the well depth.

When pumping fluid from a well with the typical single acting pumps, the weight of the column of fluid in tubing 5 and the weight of the pumping string are carried and moved during the up stroke by wire line 9, the drum 14, gear transmission devicer20 and motor 32. But during the down stroke, the weight of the uid column is carried by tubing 5, and the weight of the pumping string is carried by wire line 9. These weights are considerable in amount and, during the down stroke, the effect of the force of gravity is to pull on drum 14, to unwind Wire line 9, thus causing the drum to rotate and to impart corresponding rotative movement through chain 19 to gear transmission device 20 and motor 32. Also,

when clutch 22a is closed, rotative movement is imparted through chain 23 to sprocket 24 and the gear train in oscillator 25. Positive power is thus required for the upward pumping stroke, whereas for the downward pumping stroke, the kinetic energy of the descending weight is converted into power which drives through drum 14, gear transmission device 20 and motor 32, and because of the well-known regenerative or dynamic braking characteristics of the electric motor, the power thus converted is returned to the supply system and, furthermore, the rate or velocity of downward movement of the pumping string is controlled and restricted within desired limits.

The function of oscillator 25 is to control the automatic periodic oscillation of drum 14, and, as more fully explained hereinbefore, this result is accomplished when clutch 22a is closed, so that sprocket 22 is secured to the drum shaft 15 and is thereby enabled to drive sprocket 24 of the oscillator 25, through chain 23. In order to eiect automatic operation of the system, the hand wheel 31 of controller 30 is utilized as hereinbefore explained to start motor 32, and then clutch 29 is closed by hand so as to engage sprocket 28, whereupon the oscillator 25 is supplied with power, which it transmits through sprocket 26 and chain 27 to sprocket 28 to rotate controller 30 automatically and periodically in each direction, thereby periodically reversing the rotation of motor 32, gear transmission device 20, drum 14 and the oscillator 25 itself.

The periodicity or frequency of the oscillations caused by the reversals is predetermined by the number of revolutions of the drum 14 in either direction and, as previously explained, this condition is governed by the desired length of pumping stroke. In my present invention I cause such reversal of the drum 14 only on the completion of the upward stroke of the pumping string, so that a complete down and up stroke of wire line 9 and the pumping string is made without changing the direction of rotation of motor 32, gear transmission device 20 and drum 14, as hereinafter more fully explained.

Referring to Fig. 1, the swivel clamp l2, which secures the Wire line 9 to drum 14, enables the wire line to be wound in either direction on drum 14 freely and without injury to the line, as more fully explained above. With rotation of drum 14 and chain 19 as shown by the arrows, wire line 9 will unwind from drum 14 and the pumping string will be lowered for its down stroke. Continued rotation of drum 14 in the same direction brings the wire line into the position indicated by dotted lines 9a, where unwinding ceases and winding begins. Movement of the pumping string has now ceased, for it is at the bottom of its down stroke. Further rotation of the drum 14 in the same direction brings the wire line to the position indicated by dotted lines 9b, where it is being wound on the drum and hoisting the pumping string for its up stroke.

When drum 14 has made the predetermined d number of revolutions corresponding to the topmost limit of the upward pumping stroke, oscillator 25 automatically rotates controller 30 from its forward running position, back through off position and into the opposite running position, r

thus correspondingly reversing the rotation of motor 32. Upon cutting off the power supply to motor 32, the upward movement of the pumping string ceases more or less gradually, depending somewhat upon the flywheel eect of the rotating parts; vthen the -heavy pumping string starts downward b y reasonof gravityand, as ,previously explained, causes the drum 14, the gear transmission device 20. and the motor 32 to rotate in the opposite direction. By the time the electrical lcircuits are closed and motor 32 again connected to the power supply system, the motor will have .come practically up .to speed. lThus the reversal of `motor 3.2, gear transmission device 2O and ldrum 14 .at the desired speed, is brought about with no draft of current or power from the power supply system; instead the motor functions in itszregenerativeor dynamic braking capacity, as previously explained.

Upon the pumping string reaching the bottom of the pumping stroke corresponding to the dotted-line position 9a of the wire line in Fig. l, the motor 32, the gear transmission device and the drum 14 are at substantially full speed and, without stop or reversal of the rotating mechanism, the upstroke is made. The stored energy resulting from the fly wheel effect of the rotating parts aids the motor 32 in its transition from regenerating energy into the supply system to that of taking energy for the delivery of power for the upstroke.

Fig. 3 shows an engine, which may be of the non-reversing type, driving through a reversing gear device 50 to drum 14, and utilizing oscillator to control the reverse gear device 50 in order to effect reversals of the drum 14.

`The reversing gear device is an improved form of transmission mechanism and its function is to transmit power in either of the directions of rotation, at the same speed. gearing, shaft and bearings are protectively enclosed and lubricated in an oil tight housing 50a, and the two directions of rotation are obtained by a double faced, double acting clutch. of the disc or cone type requiring only one shifter.

Sprocket 47 on the engine shaft is connected by chain 48 with sprocket 51 of reverse gear device 50 which is of the differential gear type. Sprockets 5l and 57 are rigidly secured to sun gearwheels 52 and 53, respectively, which float on shaft 55. A pair of planetary gear-wheels 54, rotatably mounted on the shaft ends of the planetary hub 56, mesh with sun gears 52 and 53. The planetary hub 56 is rigidly secured to shaft 55. A

'l clutch disc 58 is rigidly secured to sun gearwheel 53, and a disc clutch 59 is splined to shaft so that it may be shifted to engage either disc 58 or a stationary disc 60, which may he bolted to the frame of the reverse gear device 50. The shifter 6l for moving clutch 59 along shaft 55, has lateral movement imparted thereto by the rota-- tion of threaded shaft 62, which is screwed into shifter 61. The shaft 62 also rotates to open or close throttle 43 in the pipe line 43a, which supe plies engine 41.

Drum 14 is connected by the chain 19 with sprocket 57; and sprocket 26 of oscillator 25, is connected by the chain 27 with sprocket 63, which is rigidly secured to threaded shaft 62.

Sprocket 45 on the shaft of engine 41 drives through chain 64 to sprocket 66 of tail pump 65. The function of the tail pump is to force into the storage tanks or pipe line, the oil or fluid lifted to the surface by the oil well pump and discharged into pipe 13.

The arrangement shown in Fig. 3 contemplates an engine running continuously without reversal during operation. When clutch 59 is in the neutral position shown on the drawings, no power is transmitted to or from drum 14. Forward drive to the drum is accomplished by shifting clutch 59 `to the left to engage disc 58, which unites .the differential gear members, so thatthey serve as a coupling. The reverse rotation of drum 14 is obtained by shifting clutch 59 to the right to engage disc 60, which thereby holds shaft -55 and vplanetary hub 56 stationary, so that the Aplanetary gear wheels 54 act as idlers between the sun gear `wheels 52 and 53.

In this arrangement, the oscillator 25 rotates shaft `62 and thereby shifts clutch 59 in either .direction according to vthe rotative direction of drum i4. During the down stroke the tail pump 65 is driven by the power transmitted by the drum 14, by reason of the kinetic energy of the descending pumping string, and thereby supplements the well pump in pumping operations. The load of the tail pump controls and limits the velocity of the down stroke of the pumping string.

If engine 41 be operated with steam, the reversing gear device 50 and shifter 61 may be eliminated. The engine will then drive directly from its sprocket 47 by chain 48 to sprocket 18 of drum The control of throttle 43 by oscillator 25 may be applied to lessen the steam supply during the rotation caused by the descending pumping string, and permit the engine 41 to work against a steam cushion in the engine cylinder and thus control the rate of downward movement of the pumping L string.

While I have shown my invention in a plurality of forms, it is apparent that applications thereof may be made for other purposes and uses than hereinabove described; therefore, I do not wish to be restricted to the specific structural details, circuit connections or arrangement of parts herein set forth, inasmuch as various modifications thereof may be made without departing from the spirit and scope of my invention. I desire, therefore, that only such limitations be imposed as are indicated in the appended claims.

I claim as my invention:

l. In combination; a motor, and a motor circuit controller for varying the direction of the rotation of the motor at predetermined intervals, said controller being rotated by the motor to automatically open the circuits to the motor and having gravity means for automatically subsequently closing the said circuits.

2. A self reversing dirve consisting of: a nonreversing motor coupled to a differential reversing gear having an output shaft, and a reversal regulator for operating the differential gear to periodically reverse the rotation of the output shaft in accordance with a predetermined number of the revolutions of said shaft.

3. A self reversing drive consisting of a motor, a shaft for transmitting the motor power, and reversal regulating means for automatically reversing the rotation of the shaft at predetermined intervals, said means being rotated by the motor for periodically cutting off the power transmitted by the shaft and having a gravity member for restoring the said power for effecting said reversals.

4. A self reversing drive consisting of: a motor, an output shaft, a differential gear interposed between the motor and the output shaft, and a reversal regulator interposed between the gear and the output shaft for automatically effecting successive reversals of the rotation of the output shaft at predetermined intervals.

5. In combination: a work device having a 'working member the movement of which is reprising a throttle regulator which automatically throttles the uid energy supply to the motor during the lowering movement of the drum.

'7. In combination: an actuating mechanism having a power transmitting oscillating shaft member, and a drive such as described in claim 3, connected to said shaft member.

8. In combination: a work device having a working member to be reciprocated, a drive such as described in claim 3, and means for operatively connecting said working member and said drive.

FREDERIC W. BILD. 

